Reactions of the di-µ-oxo-bis[(L-cysteinato)oxomolybdate(V)] ion

Abstract

Reactions of the complex Na₂,[Mo₂(O)₄(cyst)₂],5H₂O (cyst =L-cysteinato)(I) have been studied. In aqueous solution (pH < 6) the co-ordinated carboxylate groups of the complex are protonated and replaced by water. Complex (I) reacts with phosphate and tartrate, but not with borate, carbonate, acetate, and phthalate ions. With diazomethane the co-ordinated thiolate group of (I) is methylated and the complex decomposes. Co-ordination of ammo-acids to molybdenum(V) is facilitated by thiol groups. The following complexes have been isolated: [Mo₂,(O)₃(Etcyst)₄](Encyst = ethyl L-cysteinato)(II); [Mo₂(O)₃(qumolin-8-olate)₄,H₂O](III); [Mo₂(O)₄SO₄(phen)₂,3H₂O](IV); [Mo₂(O)₄Cl₂(phen)₂](V); [Mo₂(O)₄(MoO₄)(phen)₂],2H₂O (VI); and [Mo₃(O)₄(Etcyst)₄(phen)₂](phen = 1,10-phenanthroline)(VII), I.r., u.v., and visible spectra, and magnetic moments of the complexes are reported and structures proposed.